I'd just like to know if making custom items is possible beyond 3.3.2. I used to play on a private server around the time 3.3.3 came out, which I believe was either the Lich King himself or else the Five-mans in ICC. Either way, the devs didn't upgrade WoW past that patch (I am 90% sure it was 3.3.2) because custom items became impractical (requiring players to edit files on their computers which is already MORE illegal than playing on a non-blizz server ).
So! tl;dr: are custom items possible with the latest versions of mangos and the WoW version it supports?
On another note, What is the general opinion on how "complete" everything is? I know WoW is pretty massive and not every single detail can be accounted for but, assuming I downloaded everything that was needed, what sort of estimated percentage (where, of course, 100% is exactly blizz-like) of the game would I experience?